Conventionally, there have been known fluid heating devices comprising a first heating heater for heating the upstream side of a pipeline through which a fluid flows, a second heating heater for heating the downstream side, an upstream-side temperature detecting device for detecting the temperature of the upstream side of the pipeline, a downstream-side temperature checking device for detecting the temperature on the downstream-side, a fluid temperature detecting device for detecting a temperature within the fluid, and a microcontroller for controlling the first heating heater and/or the second heating heater. See, for example, Japanese Unexamined Patent Application Publication No. 2007-46812 (“the JP '812”). In this pipe of fluid heating device, the microcontroller controls the first heating heater and the second heating heater independently based on the respective detected temperatures of the upstream-side temperature detecting device, the downstream-side temperature detecting device, and the fluid temperature detecting device. This can prevent the occurrence of a problem wherein a portion of the pipeline dries out, making it possible to produce heated fluids, such as saturated vapors and superheated vapors, and the like, efficiently.
However, the fluid heating device set forth in the JP '812 merely detects the temperatures of the pipe and the fluid to control the temperatures of the pipe and the fluid, so changing a gas/liquid two-phase fluid to a desired flow state, such as a saturated vapor, is difficult.
The several forms of the present invention contemplate the problem described above, and an aspect thereof is to provide a flow state controlling device and flow state controlling method wherein a gas/liquid two-phase flow fluid can be put easily into a desired flow state.